Six weeks before Lehman Brothers went under, Shiv Verma tells us, he joined a hedge fund as the world felt like it was falling apart. After building structured-credit and CLO models at J.P. Morgan from 2006 to 2008, Verma says he helped buy back assets originated at par for five cents on the dollar.

A mentor there supplied a rule Verma still carries: “The best trade you ever make is often the trade you don’t make.”

For Robinhood’s CFO, the line offers a double meaning—and a little fun. In the interview, however, Verma applies it to corporate resource allocation. According to Verma, it is easy to make an investment, become excited, and sell yourself on the idea. The harder work is asking the right questions and “knowing when to say no.”

That standard reaches beyond securities. Verma says he applies it when Robinhood considers funding an investment, approving a marketing campaign, or pursuing an acquisition. Restraint is not timidity: Robinhood wants to grow and say yes to many opportunities, he tells us, while balancing business enablement and controllership.

According to Verma, acquisitions must offer technology, talent, or greater speed to market, generally accelerating Robinhood by 18 to 24 months. They must also pass the company’s IRR, NPV, and internal thresholds.

The title may wink playfully at Robinhood’s trading platform, but Verma’s underlying finance lesson is serious: sound capital allocation is ultimately defined not only by the opportunities a CFO pursues, but also by those finance has the judgment to decline.